Common Exterior Foundation Waterproofing Membrane Applications

Mar 7, 2012 • By Matthew Stock.

You’ve got a beautifully finished basement and you are starting to get water seeping in. How can you make this nightmare go away before your belongings start getting damaged? Some waterproofing companies will tell you that you need to do the job from the inside. They may recommend interior drain tile, but that will involve a lot of prep work, including such tasks as removing carpeting and possibly taking down drywall or paneling. A full service waterproofing company will have a variety of solutions. One possibility is dealing with the problem on the exterior of your home, so you don’t have to do any repairs inside. Keeping the water outside your home is what an exterior foundation waterproofing membrane does best.

What is an exterior foundation waterproofing membrane?

Essentially, an exterior foundation waterproofing membrane is a waterproof barrier for below ground application to your foundation. Typically they are rolled-good or sheet products that are liberally affixed to the wall, or cold fluid applied sealants made of flexible asphalt modified polyurethane that can be applied to the foundation with a hand trowel, a roller or with spray equipment. The benefit of the liquid product is that upon curing, it becomes a single seamless unit designed to protect your home from water penetration, while still allowing the normal expansion and contraction due to heat and cold.

What are the common applications for exterior foundation waterproofing membranes?

Grading Problems: The elevation of the grading around the home is often an issue. Does your home have a sidewalk, patio, or a driveway right next to it? If your patio, for example, is located right next to the house and sits higher than the top of the foundation wall, you could get “over the top seepage”. After a rain or melting snow, water pooling on your patio seeks a lower point and flows next to and over the top of the foundation wall creating the seepage inside. The application of an exterior foundation membrane in that area would eliminate this problem. Exterior membranes can be applied in small, problem areas or around an entire structure, from the footing to the top of the foundation wall.

Porous Foundations: Problems can also be due to the type of foundation wall in your home. Poured concrete walls tend to crack, but each crack can be treated individually. Masonry foundation walls are constructed of brick, concrete block, telephone tile or stone, (all of which can be porous) and all use mortar to bind the pieces together. The mortar is weaker than the masonry units and over time, water will slowly wash away the mortar that holds the wall together. Cracks can also begin to develop due to the weakened mortar and the settling of the foundation. Water will begin to penetrate the mortar and the situation will continue to worsen unless remedied.

To create the waterproof barrier with an exterior membrane for a foundation wall, the earth (and paving, where applicable) next to the wall must be excavated, either by hand or machine. This digging is costly, but necessary to get at the problem. After the wall is prepped and the membrane is applied, the benefits are two-fold in that the seepage will not continue in your basement and the membrane will also help to maintain the structural integrity of your wall.

Remember, the most important part of doing any job is having the KNOWLEDGE and EXPERIENCE necessary to do the job right. Having the tools and materials to do the job is only half of what you need. Would you trust a guy without a doctor’s degree to diagnose your medical condition, just because he had a stethoscope? Well, if you want to get your seepage problem diagnosed and repaired the right way, contact a reputable basement waterproofing company!